Fumigating pump



ct. 1,v 1935. w, D. MERRlLL 2,015,723

FUMIGATING PUMP Filed Deo. 18, 1931 5 Sheets-Sheet 1 W. D. MERRILL FUMIGATING PUMP Oct. l, 1935.

' 5 sheets-sheet 2 Filed Dec. 18, 1931 aan fr wQD. MERRILL FUMIGATING PUMP Oct. l, 1935.

3 Sheets-Sheet 5 Filedv Dec. 18, 1931 Patented Oct. 1, 1935 PATENT OFFICE FUMIGATTNG PUMP Wallace D.,Merrill, Sierra Madre, Calif., assignor, by mesne assignments, to American Cyanamid & Chemical Corporation, a corporation of Delaware Application December 18, 1931, Serial No. `581,862

6 Claims.

The present invention relates to a device for pumping liquids and. is particularly applicable to the dispensing of liquid fumigants, such as liquid hydrocyanic acid, in measured doses.

, In the fumigation of enclosed spaces by means of liquid hydrocyanic acid, Yit is desirable to provide dispensing means for such fumigants of a character which will enable the operator to accurately gauge the dosage to be pumped or ejected, and the invention is particularly directed to aV pump of the above type.

In the useof liquid hydrocyanic acid as a fumigant, the pumping or dispensing devices of the piston type usually contain a hose or other tubular element attached to thepumping device whereby the liquid hydrocyanic acid may eitherbe sprayed from the end of the tube or hose into the space to be fumigated or through any approved system of heat transfer be gasied before ejection from the end of the tube or hose. In devices of the type described above, therehas heretofore been some difficulty in the field due to the fact that air or gas pockets form beneath the piston, and/ or at the end of the down-stroke of the piston used to force the fumigant into the tube and Vout of the nozzle, a certain amount of the liquid remained in the pump barrel. Where the fumigant discharge aperture is at or near the bottom of the pump, as is usual,A the air bubbles or formed gas bubbles hang inthe space beneath the piston and are only expelled if a suiciently high velocity of the outgoing liquid obtains. Gas or air pockets are put undercompression .by the piston and-cause a discharge or dribble after the completion of the pump stroke, due to expansion. This necessarily causes inaccurate dosage. Due to thefact that the 4outlet for this liquid, that is, the connection between the pump barrel and the dispensing hose, was substantially at the bottom uof the formerand in close .proximity to the `headof the piston at the end of 'its stroke, dribbling frequently occurred. This is a verydangerous circumstance, particularly when using liquid hydrocyanc acid highly toxic to life even `inslnall quantities.

One ,of the principal objects of the-invention,

therefore, is to devise a pump system which Awill prevent this dribbling or undue leakage ,of liquid fumigant after the end of the pump stroke has been reachedwhether due to trapped and expanding gas or gravitational flow. i

In carrying out the invention,.I may accomplish the above result by placingthe connection between the dispensing tube and Athe pump barrel `at or nearO the topof the latter so `that any .gas

(Cl. 10B-178) or air bubbles will immediately rise and pass out through the discharge opening, and the tendency for any liquid remaining `in the pump barrel to escape through the tubes is considerably lessened.

Other important features of the invention reside in the provision of a substantially cylindrical piston operable within a pump barrel or casing upon which is superimposed a dome within which the piston may rise. The top of the piston is arranged to be open and the bottom thereof is provided with a valve mounted Von the end of the piston rod, the rod being soarranged that during the rst portion of its up stroke, the valve is unseated and during the remainder of its up stroke, the entire piston is carried upwardly into the dome. An inlet for the liquid fumigant is provided in the pump, and due to the fact that the top of thepistonis open, the fumigant under the action of gravity ows into the inside of the piston, and when the valve in the bottom of the piston has been unseated on the first portion of the up stroke of the Ypiston rod, the liquid fumigant flows through the valve to `a point beneath the head ,ofthepiston as the latter is raised to the desired extent, depending upon the dosage desired.` A flexible washer having a depending skirt of material extent surrounds the cylindrical piston to prevent the passage of liquid fumigant from the pump barrel Lpast the walls of the piston and into the dome. In order to insure the prevention of this escape and consequent inaccuracy of dosage, a coilV spring is located in the head of the pump barrel or casing and surrounds the depending skirt of the washer. The -spring is so arranged that it forcibly bears against the skirt and thus insures close contact between the washer and the piston. AWhile the spring `is not essential, it is highly desirable as a precautionary measure. This feature Ainsures sufficient friction between the washer and the piston to prevent dropping of the latter under action of Vits own weight ahead of the dosage stroke, with consequent dribbling and inaccurate dosage.

The invention further consists in the novel arrangement, `combination and construction of parts more fully hereinafter shown and described. In the drawingsb Y Fig. 1 is a side elevation of a device embodying Ymy invention,

' 50 Fig. 2 is a frontelevation of the device of Fig. l,

Fig. 5 is a fragmentary elevation of the dosage adjustment mechanism,

Fig. 6 is a sectional view along the line 6 6 of Fig. 5, and l 5 Fig. 7 is a perspective View of the stepped sched- Referring now with particularity to the embodiment illustrated, I have shown a base at I upon which is mounted a pump barrel or casing com- 10 prising a bottom casting 2, the barrel or casingV proper 3, and an upper casting 4. The parts 2, 3 and 4 will be referred Yto generally hereafter as the pump barrel 3. Y

Suitably mounted upon the upper casting 4 is a dome 5 provided with a valved fluid inlet 6 carrying a strainer housing 6a. Y

As shown in Fig. 3, a piston is located within the pump barrel 3 consisting of a cylindrical portion 1 spaced from the walls thereof. The top of the piston 1 is open to permit a liquid entering the dome at 8 to flow thereinto.

Suitably mounted inthe top 9 of the piston 1 is a bushing III through which a piston rod II passes.V At the bottom of the piston rod is located a valve I2l adapted to seat in the center of the piston head I3. portion of the piston rod II is a spacer tube I4, the top of which terminates short of the bottom of the bushing I0. This is for the purpose of permitting the valve I2 to unseat during the first portion of the upward movement of the piston rod II or until the top of the tube I4 contacts with the bottom of the bushing I0. The upper portion of the dome is provided with a cavity through which the piston rod II passes, and the cavity isV provided'with the usual packing I5, follower I6 and packing nut I1.

, In order to insure the prevention of escape of .liquid from beneath and around the piston to a 40 Apoint within the dome, which would consequently cause irregularity and inaccuracy in dosage, a flexible washer I8 is provided secured between the upper casting 4 of the pump barrel and a ring Y member I9. The washer is provided with a depending skirt 20 making substantial surface contact with the piston 1, and a coil spring 2| is provided located within a recess in theupper casting 4 and forcing thedepending skirt 20 of the washer I8 into close and intimate'contact with Vthe outer walls of the piston 1. In order to prevent the hardening of and consequent lowering of the efficiency of the washer I8, means are provided to lubricate the same. This may conveniently consist of an oil cup 22 provided with the usual valve 23, the cup 22 communicating with a conduit 24, the oil passing therefrom into the oil groove 25 in the ring I9 to the washer. The mere adjustment of the valve 23 will cause suitable distribution of the oil over the entire surface of the washer I8.

The lower casting 2 is provided with a sediment trap 26 and drain valve 21 through which any scale or other accumulation may be removed as desired.

Y Set into the upper casting 4, which is at or near the top of the pump barrel, is a liquid outlet 28 containing a checkvalve which communicates by means'of the bore 29 with the space between the piston 1 and the pump barrel 3.

In order to operate the p-iston rod and piston,

' a pump lever 39 is provided, being pivoted to the top of the piston rod as at 3| and fulcrumed on top of `the link 32 pivotally carried as at 33 on if the support 34. The support 34 is provided with 15Y two legs, one of which is secured to the top of Surrounding the lower Y the dome 5 and the other to the bottom flange of the dome. The opposite end of the pump lever terminates in a handle member adapted to be grasped by the operator.

The dosage may be fixed and determined by 5 means of an adjustment mechanism. Operation of the dosage control and its means of adjustment is as follows:

A stepped schedule device comprising steps 49 and 40a are adjustably secured to the top of lever 10 30 as by means of screws or the like. The height of the steps on member 4D is about five times the height of those on member 49a.. Pressing the lever 30 to therright side of the frame 31 and raising until the step on member 48a. is stopped 15 by adjustment screw 4I, lifts the piston to such a height that the down stroke will eject a one unit dosage.

Pressing the lever 30 to the left side of frame 31, and raising until the step on member 40 is 20 stopped by adjustment 39, lifts the piston to such a height that the down stroke will eject ve units.

Obviously any other desired relationship between the members 40 and 49a and stops 39 and 4I may be used to eject other multiples of units. 25

It will be noted that there is sufficient side play between the lever 3D and the rigid frame parts 3B and 31 to permit the lever to be raised past the one unit stop 4I when a greater amount is to be ejected. Y

The lever 39 may conveniently carry designations indicating the dosage when the members 40 and 40a are in any particular position, as shown in Fig. 5. For example, as shown with the setting of this figure, when the lever is pressed to the 35 right to use the one unit schedule 48a, 18 cc. will be ejected on the down stroke, while if the lever is pressed to the left to use schedule 40, the five unit member cc. will be ejected.

In operation, the parts 39, 4U and 4I having been 40 adjusted to permit an up stroke of a predetermined extent, the piston being in the full down position, liquid fumigant is permitted to flow through the inlet valve B and strainer 6a until a desired level has been reached within the device 45 which will at least be to the level of the inlet 8. This will fill the interior of the piston with liquid. Upon the first portion of the up stroke of the piston rod II, the valve I2 will unseat. Further upward movement of the piston rod will carry the 50 entire piston with it. From this movement the liquid within the piston spills under the valve I2 through the piston head I3 and into the pump barrel. Upon the first portion of the down stroke movement, the Valve I2 will seat on the piston 55 head and further downward movement will force v the fumigant upwardly between the walls of the piston 1 and the pump barrel 3 through the pump 29 and out of the outlet 28 to the distributing nozzle or tube (not shown). This top discharge is 60 to eliminate air or gas pockets which cause dribble when expanding after being put under compression by the stroke. This is a very important feature.

The coil spring 2| being under tension, intimate 65 and forced contact is made between the skirt 20 of the washer and the piston 1, thus preventing any escape of fumigant back into the dome 5 during the down stroke of the piston. This makes for accuracy of dosage. 70

While the invention has been shown and described with particular reference to a specific embodiment, yet the inventionY is not to be limited. thereto but is to be construed broadly and restricted only by the scope of the claims.

I claim:

l. A displacement pump for volatile liquids comprising a pump barrel, including upper and lower portions, an annular washer attached to said barrel between said upper and lower portions, an inlet located in said upper portion, a valved outlet located in the upper part of said lower portion, and a movable piston located in said barrel and comprising a valved head cooperating with a piston rod and a cylindrical skirt portion of substantially smaller diameter than the internal diameter of the barrel and of suilicient length to contact with said washer during the entire stroke of the piston.

2. A displacement pump for volatile liquids comprising a pump barrelincluding upper and lower portions, an annular washer attached to said barrel between said upper andlower portions, an inlet located in said upper portion, a valved outlet located in the upper part of said lower portion, a piston rod in said barrel having a piston mounted on the end thereof and capable of limited movement with respect thereto, said piston consisting of an apertured head cooperating with the end of said piston rod to form a valve and a cylindrical skirt portion of substantially smaller diameter than the internal diameter of' said barrel and oi sufficient length to contact with said washer during the entire stroke of the piston.

3. A displacement pump for volatile liquids comprising a pump barrel including upper and lower portions, an annular washer attached to said barrel between said upper and lower portions, an inlet located in said upper portion, a valved outlet located in the upper part of said lower portion, a movable piston located in said barrel and comprising an apertured head, a skirt portion of substantially smaller diameter than the internal diameter of said barrel and of suincient length to contact with said washer during the entire stroke of the piston, and an apertured web mounted on said skirt portion, anda piston rod slidable mounted in said web for limited relative movement therewith and having an end portion forming a valve seating in the aperture in said head.

4. A displacement pump for volatile liquids comprising a pump barrel including upper and lower portions, an annular washer attached to said barrel between said upper and lower portions,

an inlet located in said upper portion, a valved outlet located in the upper part of said lower portion, a piston rod in said barrel having a tapered end forming a valve and an intermediate portion of altered cross section, and a movable 5 tapered end of said piston rod.

5. A displacement pump for volatile liquids comprising a pump barrel including upper and lower portions, an annular washer attached to said barrel between said upper and lower portions and comprising a exible skirt portion and means for urging said skirt portion inwardly, an inlet located in said upper portion, a valved outlet located in the upper part of said lower portion, and a movable piston located in said barrel and comprising a valved head and a cylindrical skirt portion of substantially smaller diameter than the internal diameter of the barrel and of suiicient length to contact with said washer during the entire stroke of the piston.

6. A displacement pump for volatile liquids comprising an outer casing, a pump barrel within said casing, an annular groove in the wall of said pump barrel, an outlet connected with said groove, an annular washer having a flexible skirt portion overhanging said groove and dividing said pump barrel into upper and lower portions, a coil spring in said annular groove and encircling the washer skirt, an inlet in the upper portion of said pump barrel, a piston rod in said barrel having a piston mounted on the end thereof and capable of limited relative movement with respect thereto, said piston comprising an apertured head cooperating with the end of said piston rod to form' a valve and a cylindrical skirt portion of substantially smaller diameter than the internal diameter of said barrel and of suiicient length to contact with said washer during the entire stroke of the piston.

' WALLACE D. MERRILL. 

